1. Field of the Invention
The present invention relates to a winding mechanism and, more particularly, to a winding mechanism for a window blind.
2. Description of the Related Art
A conventional winding mechanism for a window blind in accordance with the prior art shown in FIGS. 8-10 comprises a base 10 having a hollow inside formed with a receiving chamber 101 and having two opposite end walls each formed with an opening 102 and a locking hole 103, a threaded rod 11 rotatably mounted on the base 10 and having an inside formed with a square drive hole 111, a square drive shaft extended through the drive hole 111 of the threaded rod 11 to rotate the threaded rod 11, a guide disk 12 having an inner wall formed with a threaded guide hole 121 screwed onto the threaded rod 11 and a peripheral wall formed with a limit hole 122, and a limit rod 14 extended through the limit hole 122 of the guide disk 12 and having two ends each secured in the respective locking hole 103 of the base 10. The base 10 has a bottom wall formed with a cord passage 104. The threaded rod 11 has two ends supported by the openings 102 of the base 10. The threaded rod 11 has a side formed with an annular flange 112 having a fixing hole 113. The guide disk 12 has an outer wall formed with a guide groove 123. A lift cord 20 has a first end secured in the fixing hole 113 of the threaded rod 11 to rotate with the threaded rod 11 and a second end extended through the guide groove 123 of the guide disk 12 and the cord passage 104 of the base 10 and protruded outwardly from the base 10 to connect a plurality of slats (not shown).
In operation, when the drive shaft 13 is rotated, the threaded rod 11 is rotated relative to the base 10 to wind or unwind the lift cord 20. At this time, the guide disk 12 is limited by the limit rod 14 so that the guide disk 12 is axially movable on the threaded rod 11 by guidance of the limit rod 14 and is not rotatable with the threaded rod 11 when the threaded rod 11 is rotatable relative to the base 10. Thus, when the threaded rod 11 is rotatable relative to the base 10, the guide disk 12 is axially movable on the threaded rod 11 as shown in FIGS. 9 and 10, so that when the lift cord 20 is wound around the threaded rod 11, the guide disk 12 is movable on the threaded rod 11, and the lift cord 20 is wound around the threaded rod 11 by guidance of the guide disk 12.
However, the limit rod 14 provides a resistance to the guide disk 12 during the axial movement of the guide disk 12, so that the guide disk 12 is not moved easily and smoothly, thereby affecting the winding and unwinding action of the lift cord 20. In addition, when the guide disk 12 is movable to the outermost portion the threaded rod 11, the guide disk 12 is easily jammed due to an excessive force applied on the guide disk 12, thereby affecting or failing operation of the winding mechanism.